SAN TAN VALLEY, Ariz., May 2 (UPI) -- An Arizona teen who posted bail Monday after being arrested for multiple sex crimes against one underage girl has been re-arrested, the number of potential victims now up to 18, possibly more, authorities said Thursday.

After arresting the 18-year-old Monday on two counts of sexual assault and two counts of sexual misconduct with a minor, Police began investigating allegations that Tyler Kost assaulted twelve other girls. Now five additional victims have been identified.

"Once we started looking at it, it immediately started to mushroom," said Pinal County Sheriff Paul Babeu. "We absolutely believe there will be far more victims that are out there."

According to sheriff's spokesman Sgt. Pat Ramirez, investigators say the victims range in age from 13 − 17.

KPHOI reports that Kost threatened, harassed, and blackmailed his victims, telling one girl to kill herself and then continuing to harass her while she was hospitalized after attempting suicide. The girl eventually fled the state.

"One of the victims actually became pregnant because of the sexual assault, and she subsequently had an abortion," Babeu said. "These are horrible crimes that cannot be tolerated in our community."

During a press conference Friday, Babeu called Kost a "serial sex offender and rapist,” and said that because Kost was youthful and attractive, he was not perceived as a threat, because he was charismatic, his victims trusted him.

According to Babeu, "He would assault these young female victims in their own bedrooms, in his bedroom, in the desert, at a community pool, at community parks.”

A probable cause statement released by authorities reads: “Tyler is smart, manipulative and a smooth talker. He is also obsessive and controlling. Tyler believes everyone else is wrong. That is how he is able to victimize so many people."

Kost has been banned from his high school.

In addition to the original charges he received during his initial arrest, Kost is facing a total of 25 new counts.

A judge denied Kost bond Friday. He is currently being held and will remain in custody.

Babeu says the investigation is ongoing and more charges will likely be filed.

If you have any additional information about the case, please call PCSO at 520-866-5161.

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